no-base-to-string.test.ts

import rule from '../../src/rules/no-base-to-string';
import { RuleTester, getFixturesRootDir } from '../RuleTester';

const rootDir = getFixturesRootDir();
const ruleTester = new RuleTester({
  parser: '@typescript-eslint/parser',
  parserOptions: {
    ecmaVersion: 2018,
    tsconfigRootDir: rootDir,
    project: './tsconfig.json',
  },
});

ruleTester.run('no-base-to-string', rule, {
  valid: [
    "`${''}`;",
    '`${true}`;',
    '`${[]}`;',
    '`${function() {}}`;',
    "'' + '';",
    "'' + true;",
    "'' + [];",
    'true + true;',
    "true + '';",
    'true + [];',
    '[] + [];',
    '[] + true;',
    "[] + '';",
    '({}.constructor());',
    "'text'.toString();",
    'false.toString();',
    `
let value = 1;
value.toString();
    `,
    `
let value = 1n;
value.toString();
    `,
    `
function someFunction() {}
someFunction.toString();
    `,
    'unknownObject.toString();',
    'unknownObject.someOtherMethod();',
    '(() => {}).toString();',
    `
class CustomToString {
  toString() {
    return 'Hello, world!';
  }
}
'' + new CustomToString();
    `,
    `
const literalWithToString = {
  toString: () => 'Hello, world!',
};
'' + literalToString;
    `,
    'let _ = {} * {};',
    'let _ = {} / {};',
    'let _ = ({} *= {});',
    'let _ = ({} /= {});',
    'let _ = ({} = {});',
    'let _ = {} == {};',
    'let _ = {} === {};',
    'let _ = {} in {};',
    'let _ = {} & {};',
    'let _ = {} ^ {};',
    'let _ = {} << {};',
    'let _ = {} >> {};',
    `
function tag() {}
tag\`\${{}}\`;
    `,
    {
      code: `
        function tag() {}
        tag\`\${{}}\`;
      `,
      options: [
        {
          ignoreTaggedTemplateExpressions: true,
        },
      ],
    },
  ],
  invalid: [
    {
      code: '`${{}})`;',
      errors: [
        {
          data: {
            certainty: 'will',
            name: '{}',
          },
          messageId: 'baseToString',
        },
      ],
    },
    {
      code: '({}.toString());',
      errors: [
        {
          data: {
            certainty: 'will',
            name: '{}',
          },
          messageId: 'baseToString',
        },
      ],
    },
    {
      code: "'' + {};",
      errors: [
        {
          data: {
            certainty: 'will',
            name: '{}',
          },
          messageId: 'baseToString',
        },
      ],
    },
    {
      code: "'' += {};",
      errors: [
        {
          data: {
            certainty: 'will',
            name: '{}',
          },
          messageId: 'baseToString',
        },
      ],
    },
    {
      code: `
        let someObjectOrString = Math.random() ? { a: true } : 'text';
        someObjectOrString.toString();
      `,
      errors: [
        {
          data: {
            certainty: 'may',
            name: 'someObjectOrString',
          },
          messageId: 'baseToString',
        },
      ],
    },
    {
      code: `
        let someObjectOrString = Math.random() ? { a: true } : 'text';
        someObjectOrString + '';
      `,
      errors: [
        {
          data: {
            certainty: 'may',
            name: 'someObjectOrString',
          },
          messageId: 'baseToString',
        },
      ],
    },
    {
      code: `
        let someObjectOrObject = Math.random() ? { a: true, b: true } : { a: true };
        someObjectOrObject.toString();
      `,
      errors: [
        {
          data: {
            certainty: 'will',
            name: 'someObjectOrObject',
          },
          messageId: 'baseToString',
        },
      ],
    },
    {
      code: `
        let someObjectOrObject = Math.random() ? { a: true, b: true } : { a: true };
        someObjectOrObject + '';
      `,
      errors: [
        {
          data: {
            certainty: 'will',
            name: 'someObjectOrObject',
          },
          messageId: 'baseToString',
        },
      ],
    },
  ],
});